After growing steadily for several decades, passenger vehicle miles traveled (VMT) in the United States unexpectedly leveled off in the 2000s. The growth rate of VMT has since rebounded, and determining the factors that explain these developments has implications for future U.S. oil consumption and vehicle pollution. We show that changes in the demographics and economic characteristics of households in the United States, rather than in driving habits, explain most of the recent dynamics. This suggests that over the next decade, VMT in the United States will continue to grow roughly at historical rates, causing substantially higher oil consumption and pollution than if persistent changes in driving habits explained the recent changes in VMT. The projected VMT growth will raise the cost of meeting energy security, climate, and local air quality objectives.